Abstract:

Objective: To optimize the expression and purification conditions of recombinant protein LuxS. Methods: The
induction conditions, including medium components, induction temperature, bacterial biomass before induction, induction
time and IPTG concentration were optimized by single-factor design. Recombinant protein was purified using Ni-NTA
purification system under native conditions. The optimum native elution buffer was determined by comparing the effects of
imidazole concentration and native elution buffer pH on purification efficiency. The optimum binding buffer for protein and
resin was determined by comparing the effects of different types of binding buffer on purification efficiency. Results: The
optimum conditions for expression of recombinant protein were determined as follows: when the OD600 nm reached 0.6–0.8,
using LB medium as the induction medium, the induction was initiated with 0.1 mmol/L IPTG at 37 ℃ for 12 h. PBS buffer
containing 3 mol/L NaCl was used for the binding of protein and resin. The recombinant protein was eluted with native elution
buffer (pH 6.5) containing 500 mmol/L imidazole. The biological activity of the synthesized AI-2 in vitro, which was produced
catalytically by Pfs and recombinant protein LuxS obtained in this study, was approximately 6-fold higher than that from the
positive control. Conclusion: The expression and purification conditions of recombinant protein LuxS were optimized, and the
recombinant protein LuxS with bioactivity was obtained. Finally, AI-2 was synthesized successfully in vitro.

Key words: recombinant protein, LuxS, induced expression, purification, autoinducer-2 (AI-2)